In seismic exploration,the low frequencies have played a significant role in increasing the resolution of seismic images in recent years.In practice the geophones usually have 10 Hz natural frequency,which indicates the distortion of the seismic signals bellow 10 Hz.The broad replacement of 10 Hz geophones with the low-frequency geophones can get "real" low frequency.This replacement process however,meets with many challenges, such as difficulties in research,long period of experiments,and high cost of low-frequency geophones.To mitigate the difficulties caused by these challenges the authors propose a practical method to estimate and recover the valid low frequencies of the conventional geophone data. In order to solve the problem of low frequency distortion in conventional geophone seismic data,the author put forward a practicable conventional low-frequency detector recovery method for low frequency geophone and,on the basis of homologous concurrent data,estimated the lowest effective frequency of conventional geophone and constructed the inverse filtering operator so as to realize low frequency recovery of conventional geophone seismic data.The practical application of B3Q shows that this technique can effectively recover the low frequency information of the conventional detector,expand the effective frequency doubling of seismic data,and improve the seismic data for solving the problem of lithology,thus having a broad application prospect.